Poly[[diaqua­bis­(2,2′-bipyridine)­bis­(μ(3)-5-hy­droxy­isophthalato)(μ(2)-5-hy­droxy­isophthalato)digadolinium(III)] trihydrate]

The asymmetric unit of the title coordination polymer, {[Gd(2)(C(8)H(4)O(5))(3)(C(10)H(8)N(2))(2)(H(2)O)(2)]·3H(2)O}(n), contains two Gd(III) cations, one of which is surrounded by three 5-hy­droxy­isophthalate anions, one 2,2′-bipyridine ligand and two water mol­ecules in a distorted N(2)O(7) tricapped trigonal–prismatic coordination geometry. The other Gd cation is coordinated by four 5-hy­droxy­isophthalate anions and one 2,2′-bipyridine ligand in a distorted N(2)O(7) tricapped trigonal–prismatic coordination geometry. The 5-hy­droxy­isophthalate anions bridge the Gd cations, forming a layer structure. The layers are further connected by extensive O—H⋯O hydrogen bonding, assembling a three-dimensional supra­molecular network.